Seatback rotating device

ABSTRACT

Provided is a seatback rotating device. The seatback rotating device includes an electric motor and an application mechanism. The electric motor generates a rotational force that is used to rotationally displace a seatback of a vehicle seat. The application mechanism enables application of the rotational force to the seatback. The application mechanism has a configuration that enables the seatback to be self-rotatable with gravity applied to the seatback in response to the rotational force being applied to the seatback.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Patent Application No.2019-19730 filed on Feb. 6, 2019 with the Japan Patent Office, theentire disclosure of which is incorporated herein by reference.

BACKGROUND

The present disclosure relates to a seatback rotating device that isused to rotate a seatback of a vehicle seat to be mounted in a vehicle.

For example, a seatback rotating device disclosed in Japanese UnexaminedPatent Application Publication No. 2012-188084 (Patent Document 1)comprises a spring (spiral spring) for tilting a seatbackseat-frontward. In this seatback rotating device, a sector gear isrotated to a return-standby position, to thereby inhibit the seatbackfrom tilting at a high speed.

SUMMARY

In the present disclosure, it is desirable to provide one example of aseatback rotating device that can inhibit a seatback from tilting at anexcessively high speed and, at the same time, can eliminate need of aspring used for tilting or rotationally displacing the seatback.

It is desirable that the seatback rotating device of the presentdisclosure comprises, for example, at least one of the followingconstituent elements.

Specifically, the constituent elements are an electric motor and anapplication mechanism. The electric motor generates a rotational forcethat is used to rotationally displace a seatback of a vehicle seat. Theapplication mechanism enables application of the rotational force to theseatback. The application mechanism has a configuration that enables theseatback to be self-rotatable with gravity applied to the seatback inresponse to application of the rotational force.

The seatback of the vehicle seat starts rotating in response to rotationvia the application mechanism. In response to this, the seatback can beplaced in a self-rotatable state with the gravity applied to theseatback.

During self-rotation, a rotational speed of the seatback is smallrelative to a rotational speed according to a configuration in which theseatback is rotated by a spring. Therefore, the seatback rotating devicehas a configuration that can inhibit the seatback from tilting at anexcessively high speed and, at the same time, can eliminate need of aspring that is used to tilt or rotationally displace the seatback.

Here, it is desirable that the seatback rotating device includes thefollowing configurations.

It is desirable that the application mechanism includes a rotor and anabutment target portion. The rotor rotates in response to the rotationalforce. The rotor includes a first protrusion and a second protrusionthat protrude in a radial direction of the rotor. The abutment targetportion is integrally and rotationally displaced with the seatback. Theabutment target portion enables one of the first protrusion or thesecond protrusion to contact the abutment target portion. The abutmenttarget portion experiences the rotational force in response to contactwith one of the first protrusion or the second protrusion. The secondprotrusion is disposed in a position that is displaced with respect tothe first protrusion in the rotational direction of the rotor. Theposition of the second protrusion places the second protrusion in anon-contact state with the abutment target portion in a state where thefirst protrusion and the abutment target portion contact each other.And, the abutment target portion is always present between the firstprotrusion and the second protrusion without being affected by aposition of the seatback.

According to the above configuration, in the seatback rotating device,the seatback starts rotating due to the rotational force in response toone of the first protrusion or the second protrusion contacting theabutment target portion.

The second protrusion is placed in the position that is displaced withrespect to the first protrusion in the rotational direction of the rotorand the second protrusion is always present between the first protrusionand the second protrusion without being affected by the position of theseatback.

As a result, the seatback is freely and rotationally displaceable in asection defined between the first protrusion and the second protrusion.Accordingly, a user of the vehicle seat, to which the seatback rotatingdevice is applied, can rotationally displace the seatback by manualoperation. In other words, the seatback rotating device can inhibit arotational speed of the seatback from being excessively large and, atthe same time, enables the seatback to be rotationally displaced withmanual operation.

It is desirable that the seatback rotating device further comprises acontroller that controls operation of the electric motor and thecontroller can execute a control mode. In the control mode, the electricmotor is rotated in a forward direction, to thereby bring the firstprotrusion and the abutment target portion into contact with each otherto apply the rotational force to the seatback. Thereafter, the seatbackreaches a specified first position. In response to the seatback reachingthe specified first position, the electric motor is rotated in a reversedirection to bring the first protrusion back to a specified secondposition. This configuration enables the user to rotationally displacethe seatback between the first position and the second position bymanual operation.

The second position can be a position to place the seatback in aseatable state. In this case, the user can place the seatback, which istilted, in the seatable state by manual operation.

It is desirable that the second protrusion is situated in a positionwithin a specified area defined with respect to the abutment targetportion when the seatback is placed in a tilted state and the firstprotrusion is placed in the second position. This configuration allowsthe seatback to start being immediately and rotationally displaced to bein the seatable state in conjunction with start of rotation of theelectric motor.

It is desirable that the seatback rotating device further comprises asensor that outputs a signal to the controller in response to theseatback reaching a tilt position. The signal indicates that theseatback reaches the tilt position. And, it is desirable that, duringexecution of the control mode, the controller rotates the electric motorin the forward direction until receiving the signal. This configurationensures that the seatback is placed in the tilt position.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will be described hereinafter byway of example with reference to the accompanying drawings, in which:

FIG. 1 is a view showing a vehicle seat of a first embodiment;

FIG. 2 is a view showing the vehicle seat of the first embodiment;

FIG. 3 is a view showing the vehicle seat of the first embodiment;

FIG. 4 is a view showing the vehicle seat of the first embodiment;

FIG. 5 is a view showing a lock device of the first embodiment;

FIG. 6 is a view showing the lock device of the first embodiment;

FIG. 7 is a view showing the lock device of the first embodiment;

FIG. 8 is a view showing the lock device of the first embodiment;

FIG. 9 is a view showing the lock device of the first embodiment;

FIG. 10 is a view showing the lock device of the first embodiment;

FIG. 11 is a view showing the lock device of the first embodiment;

FIG. 12 is a view showing a seatback rotating device of the firstembodiment;

FIG. 13 is an exploded view of the seatback rotating device of the firstembodiment;

FIG. 14 is a block diagram of a control system of the seatback rotatingdevice of the first embodiment;

FIG. 15 is an explanatory diagram of operation of the seatback rotatingdevice of the first embodiment;

FIG. 16 is an explanatory diagram of the operation of the seatbackrotating device of the first embodiment;

FIG. 17 is an explanatory diagram of the operation of the seatbackrotating device of the first embodiment;

FIG. 18 is an explanatory diagram of the operation of the seatbackrotating device of the first embodiment;

FIG. 19 is an explanatory diagram of the operation of the seatbackrotating device of the first embodiment;

FIG. 20 is an explanatory diagram of the operation of the seatbackrotating device of the first embodiment; and

FIG. 21 is a block diagram of a control system of a seatback rotatingdevice of a second embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

An “embodiment” to be described below is one example of embodiments thatfall within the technical scope of the present disclosure. In otherwords, matters specifying the invention recited in claims are notlimited to specific configurations, structures, and the like that areshown in the embodiments below.

At least in respect of a member or portion that is labeled with areference numeral for explanations, there is at least one in number ofsuch a member or portion unless the number is otherwise specified, forexample, as “one of”. In other words, there may be two or more of such amember or portion when the number is not specified.

In the present embodiment, descriptions are given to an example of aseat to be mounted in a vehicle such as an automobile (hereinafter,referred to as a vehicle seat). Arrows and other marks that indicate thedirections labelled on each drawing are made for easy understanding ofrelationships between the drawings.

Therefore, the invention shown in the present disclosure is not limitedto the directions labelled on each drawing. The directions shown in thedrawings are based on a state where the vehicle seat of the presentembodiment is assembled to the vehicle.

First Embodiment

1. Overview of Vehicle Seat and the Like

As shown in FIG. 1, a vehicle seat 1 comprises at least a seatback 3, alock device 10, and a seatback rotating device 20. The seatback 3 is aportion for supporting the back of an occupant.

The seatback 3 is a seatback of a vehicle seat that is used for a rearseat of a vehicle. The seatback 3 is rotatable in seat front-reardirections (in the present embodiment, vehicle front-rear directions andhereinafter simply referred to as front-rear directions).

A back frame 3A is a metal member that forms a framework of the seatback3. The back frame 3A is rotatably coupled to a vehicle body via theseatback rotating device 20 and a bracket 3B.

The lock device 10 can execute a lock mode and a released mode. The lockmode holds the seatback 3 in a first standing position (see, FIG. 2) ora second standing position (see, FIG. 3). The released mode releases thelock mode. The second standing position is displaced seat-rearward(rearward) with respect to the first standing position.

When the lock device 10 is placed in a released state, the seatback 3can tilt to a position that allows the seatback 3 to contact or come inproximity to a seat cushion 5, as shown in FIG. 4 (hereinafter, referredto as a tilt position). The seat cushion 5 is a portion for supportingthe buttocks of the occupant.

2. Structure of Lock Device

<Overview of Lock Device>

As shown in FIG. 1, the lock device 10 is fixed to the back frame 3A atan upper right end of the back frame 3A (closer to a door inner panel(not shown)). UP-down and left-right directions are the directions shownin FIG. 1. The lock device 10 is engaged with a striker 10A shown inFIG. 5A, to thereby hold the back frame 3A in the first standingposition (see, FIG. 6) or the second standing position (see, FIG. 7).

The striker 10A is one example of an engagement target member that isfixed to a vehicle body component such as the door inner panel or thelike. The striker 10A includes at least a first engagement bar 10B and asecond engagement bar 10C that extend toward the back frame 3A from thedoor inner panel.

The first engagement bar 10B and the second engagement bar 10C arespaced apart from each other across a space 10D in the front-reardirections. The first engagement bar 10B is positioned closer to a seatfront than the second engagement bar 10C is. In the present embodiment,the first engagement bar 10B and the second engagement bar 10C areone-piece article that is formed by bending a single metal bar.

<Details of Lock Device>

As shown in FIG. 8, the lock device 10 comprises at least a hook 11, astandby plate 12, a pole 13, and an operator 14 (see, FIG. 1).

As shown in FIGS. 9 and 11, the hook 11 is an engagement member that isengaged with the striker 10A (the first engagement bar 10B or the secondengagement bar 10C) in a catching manner. Therefore, the hook 11 isprovided with a recess 11A to allow the first engagement bar 10B or thesecond engagement bar 10C to fit therein.

The hook 11 is displaceable between an engaged position (see, FIGS. 9and 11) and a released position (see, FIGS. 8 and 10). The engagedposition allows the hook 11 to be engaged with the striker 10A. Thereleased position allows the hook 11 to be released from the engagement.In other words, the lock device 10 is placed in a locked state when thehook 11 is placed in the engaged position. The lock device 10 is placedin the released state when the hook 11 is placed in the releasedposition.

Specifically, the seatback 3 is held in the first standing position whenthe hook 11 is engaged with the first engagement bar 10B (see, FIG. 9).The seatback 3 is held in the second standing position when the hook 11is engaged with the second engagement bar 10C (see, FIG. 11).

The hook 11 constantly experiences an elastic force from a hook spring(not shown). The elastic force is a force for displacing the hook 11toward the engaged position. The operator 14 is a portion that isoperated by a user when the hook 11 is displaced to the releasedposition.

The pole 13 transmits an operation force, which is input in the operator14, to the hook 11. In other words, the hook 11 is displaced from theengaged position to the released position in response to the operator 14being operated. The hook 11 returns to the engaged position due to theelastic force of the hook spring in response to disappearance of theoperation force.

The pole 13 also operates with an actuator (not shown) that iscontrolled by a controller 26 (see, FIG. 14). Specifically, the hook 11is displaced between the engaged position and the released position inresponse to a control command of the controller 26.

The standby plate 12 is displaceable to (i) a first standby position(see, FIG. 8) and a second standby position (see, FIG. 10) to hold thehook 11 in the released position. The standby plate 12 is alsodisplaceable to (ii) respective two positions that are displaced fromthe positions (i) (see, FIGS. 9 and 11). In other words, the standbyplace 12 is displaceable between the positions (i) and the positions(ii).

As shown in FIG. 8, the first standby position holds the hook 11 in areleased state where the hook 11 is neither engaged with the firstengagement bar 10B nor the second engagement bar 10C.

As shown in FIG. 10, the second standby position releases the hook 11from engagement with the first engagement bar 10B and holds the hook 11in a position that allows the hook 11 to be engaged with the secondengagement bar 10C.

3. Seatback Rotating Device

<Overview of Seatback Rotating Device>

The seatback rotating device 20 rotationally displaces the seatback 3 inthe front-rear directions. As shown in FIG. 12, the seatback rotatingdevice 20 comprises at least an electric motor 21, an applicationmechanism 23 and the controller 26 (see, FIG. 14).

The electric motor 21 generates a rotational force for rotationallydisplacing the seatback 3. The electric motor 21 can rotate in a forwarddirection and in a reverse direction. As shown in FIG. 13, the electricmotor 21 of the present embodiment is integral with a decelerationmechanism 21A.

The deceleration mechanism 21A is a gear-type deceleration mechanismthat includes at least a worm and a worm wheel. The electric motor 21and the deceleration mechanism 21A are fixed to a motor bracket 21B. Themotor bracket 21B is fixed to the vehicle body component via anattaching bracket 21C.

The application mechanism 23 allows the rotational force of the electricmotor 21 to be applied to the seatback 3. Specifically, the applicationmechanism 23 is configured such that the seatback 3 is self-rotatablewith gravity applied to the seatback 3 in response to the seatback 3experiencing the rotational force that rotates the seatback 3seat-frontward (frontward).

<Detailed Configuration of Application Mechanism>

As shown in FIG. 13, the application mechanism 23 includes at least asector gear 24 and a press pin 25. The sector gear 24 is one example ofa rotor that rotates in response to the rotation force.

The sector gear 24 includes at least a gear portion 24A, a firstprotrusion 24B, and a second protrusion 24C. The gear portion 24A mesheswith an output gear 21D of the deceleration mechanism 21A (see, FIG.12). This enables the sector gear 24 to rotate in response to operationof the electric motor 21. The sector gear 24 includes a first area 24Fand a second area 24S. The first area 24F is situated between the firstprotrusion 24B and the second protrusion 24C and the first area 24Fincludes the first protrusion 24B and the second protrusion 24C. Thesecond area 24S is situated opposite to the first area 24F. The gearportion 24A is formed in the second area 24S.

The first protrusion 24B and the second protrusion 24C are portions thatprotrude in a radial direction of the sector gear 24. The firstprotrusion 24B and the second protrusion 24C, respectively, configure afirst abutment surface 24D and a second abutment surface 24E that can bebrought into contact with the press pin 25. The sector gear 24 of thepresent embodiment is a one-piece article with which the firstprotrusion 24B and the second protrusion 24C are integrally molded.

The press pin 25 is integrally displaced with the seatback 3. The presspin 25 is one example of an abutment target that can be brought intocontact with one of protrusions the first protrusion 24B or the secondprotrusion 24C, in other words, one of abutment surfaces the firstabutment surface 24D or the second abutment surface 24E.

As shown in FIG. 12, the press pin 25 is fixed to a pin bracket 25A. Thepin bracket 25A is fixed to the back frame 3A. Therefore, the press pin25 is integrally and rotationally displaced with the seatback 3.

In a state where the first protrusion 24B and the press pin 25 abutagainst each other, the rotational force, which rotates the seatback 3frontward, is ready to be input to the press pin 25. In a state wherethe second protrusion 24C and the press pin 25 abut against each other,a rotational force, which rotates the seatback 3 rearward, is ready tobe input to the press pin 25.

As the seatback 3 rotates frontward with the electric motor 21, theelectric motor 21 rotates in the forward direction. As the seatback 3rotates rearward with the electric motor 21, the electric motor 21rotates in the reverse direction. In response to rotation of theelectric motor 21 in the forward direction, the sector gear 24 rotatesin the forward direction. In response to rotation of the electric motor21 in the reverse direction, the sector gear 24 rotates in the reversedirection.

<Controller>

As shown in FIG. 14, the operation of the electric motor 21 iscontrolled by the controller 26. The controller 26 is configured with amicrocomputer that includes a CPU, a ROM, a RAM, and the like.

The controller 26 controls the operation of the electric motor 21 inaccordance with a program that is stored in advance in a nonvolatilestorage such as the ROM or the like. The controller 26 receives anoutput signal of a first sensor 26A.

The first sensor 26A outputs a signal that shows whether the seatback 3rotates frontward to a specified first position of the presentembodiment. The term “specified first position” is set between the tiltposition (see, FIG. 4) and the first standing position.

Specifically, at the first position, the seatback 3 automatically startsrotating frontward due to the gravity applied to the seatback 3. Inother words, the seatback 3 starts tilting due to its own weight whenthe seatback 3 reaches the first position.

Then, the first sensor 26A outputs a signal to the controller 26, thesignal indicating that the seatback 3 reaches the first position. Thefirst sensor 26A and the controller 26 detect whether the seatback 3reaches the first position, taking advantage of a value of a conductioncurrent, which flows to the electric motor 21, exceeding a thresholdvalue.

In the present embodiment, a stopper (not shown) is provided tomechanically stop rotation of the sector gear 24, in other words, therotation of the electric motor 21, in response to the electric motor 21rotating in the forward direction and then the seatback 3 reaching thefirst position.

In response to stop of the rotation of the electric motor 21 in aconducted state, a value of the conduction current increases. As aresult, the first sensor 26A and the controller 26 detect the increasein value of the conduction current, thus detecting that the seatback 3reaches the first position.

The controller 26 also receives an output signal of the second sensor26B. The second sensor 26B detects whether the seatback 3 is placed inthe first standing position. The second sensor 26B may be configuredwith a limit switch or a proximity switch. The second sensor 26B outputsan ON signal when the seatback 3 is placed in the first standingposition.

<Positional Relationship Between First, Second Protrusions and PressPin>

As shown in FIGS. 15 to 20, the second protrusion 24C is situated at aposition that is displaced with respect to the first protrusion 24B inthe forward direction. Specifically, a length measured from the firstabutment surface 24D to the second abutment surface 24E along arotational direction of the sector gear 24 is greater than the diameterof the press pin 25.

Therefore, in a state where the first protrusion 24B and the press pin25 contact each other (see, FIG. 17), the second protrusion 24C isplaced in a non-contact state with the press pin 25. In a state wherethe second protrusion 24C and the press pin 25 contact each other (see,FIG. 20), the first protrusion 24B is placed in a non-contact state withthe press pin 25.

The press pin 25 is always present between the first protrusion 24B andthe second protrusion 24C without being affected by a position of theseatback 3 (see, FIGS. 15 to 20). In other words, the press pin 25 doesnot contact the gear portion 24A.

When the seatback 3 is placed in the first standing position, forexample, the controller 26 places the sector gear 24 in a position thatcreates a gap between the first protrusion 24B and the press pin 25 anda gap between the second protrusion 24C and the press pin 25 as shown inFIG. 15. Hereinafter, when the sector gear 24 is placed in theaforementioned position, the sector gear 24 will be referred to as beingin a standby state.

When the sector gear 24 is placed in the standby state, a gap length L1from the first protrusion 24B to the press pin 25 is small relative to agap length L2 from the second protrusion 24C to the press pin 25. Thegap lengths L1 and L2 are lengths of the respective gaps along arotational direction of the sector gear 24 about the central axis of thesector gear 24.

Specifically, in the standby state, the gap length L1 along therotational direction of the sector gear 24 allows the seatback 3 to bedisplaced to the second standing position with the sector gear 24remaining in the standby state. The upper drawing of FIG. 16 shows thatthe seatback 3 is placed in the second standing position.

The press pin 25 shown in FIG. 16 by a solid line shows a position ofthe press pin 25 when the seatback 3 is placed in the second standingposition. The press pin 25 shown in FIG. 16 by a double-dashed lineshows a position of the press pin 25 when the seatback 3 is placed inthe first standing position.

<Tilt Control of Sector Gear (Electric Motor)>

The controller 26 executes the following tilt control mode in displacingthe seatback 3 to the tilt position when the seatback 3 is placed in thefirst standing position or the second standing position. The tiltcontrol mode is executed when the user operates a tilting operationswitch (not shown).

First of all, the controller 26 places the hook 11 of the lock device 10in the released position. Then, the controller 26 rotates the electricmotor 21 in the forward direction, to thereby bring the first protrusion24B and the press pin 25 into contact with each other to apply a forwarddirection rotational force to the seatback 3.

Then, the controller 26 rotates the electric motor 21 in the reversedirection to bring the first protrusion 24B back to a specified secondposition (see, FIG. 19) in response to the seatback 3 reaching the firstposition (FIG. 17). The second position of the present embodiment is aposition of the first protrusion 24B when the sector gear 24 is placedin the standby state.

The seatback 3 rotates frontward such that the seatback 3 tilts due tothe gravity derived from its own weight in response to the seatback 3reaching the first position (FIG. 18). Accordingly, the secondprotrusion 24C is positioned within a range specified with respect tothe press pin 25 when the seatback 3 is placed in a tilted state and thefirst protrusion 24B is placed in the second position (see, FIG. 19).

The above description “the second protrusion 24C is positioned in arange specified with respect to the press pin 25” means, for example,(a) a position where the second protrusion 24C and the press pin 25contact each other or (b) a position where a distance L3 between thesecond protrusion 24C and the press pin 25 (see, FIG. 19) is equal to orless than a specified distance. The distance L3 is a distance along therotational direction of the sector gear 24 about the central axis of thesector gear 24.

4. Operation of Seatback

In response to the controller 26 starting the tilt control mode in astate where the seatback 3 is placed in the first standing position(see, FIG. 15) or in the second standing position (see, FIG. 16), thehook 11 of the lock device 10 is placed in the released state andthereafter the electric motor 21 rotates in the forward direction.

In response to the electric motor 21 rotating in the forward directionand the seatback 3 reaching the first position (see, a solid line ofFIG. 17), the electric motor 21 rotates in the reverse direction and thefirst protrusion 24B returns to the second position. Then, the electricmotor 21 stops.

Here, the seatback 3 is already at the first position and is thereforerotationally displaced to the tilt position with its own weight (see,FIGS. 18 and 19). In response to the electric motor 21 rotating in thereverse direction in a state where the seatback 3 is placed in thetilted state (see, FIG. 19), the second protrusion 24C and the press pin25 contact each other. In response to this, the seatback 3 rotatesrearward in a standing manner.

Then, in response to the seatback 3 rotating to the first position, theseatback 3 is held in the first standing position by the lock device 10.In response to the seatback 3 being held in the first standing position,the controller 26 rotates the electric motor 21 in the reverse directionto bring the sector gear 24 back to the standby state (see, FIG. 15).

5. Features of Vehicle Seat of the Present Embodiment (Particularly,Seatback Rotating Device)

The application mechanism 23 of the seatback rotating device 20 isconfigured such that the seatback 3 is self-rotatable with the gravityapplied to the seatback 3 in response to the rotational force of theelectric motor 21 being applied to the seatback 3.

According to the aforementioned configuration, the seatback 3 startsrotating in response to the rotational force via the applicationmechanism 23 and then, the seatback 3 is placed in a self-rotatablestate with the gravity applied to the seatback 3. During self-rotation,a rotation speed of the seatback 3 is small relative to a rotation speedaccording to a configuration in which the seatback 3 rotates via aspring.

Accordingly, the seatback rotating device 20 has a configuration thatcan inhibit the seatback 3 from tilting at an excessively large speedand, at the same time, can eliminate need of a spring that is used totilt or rotationally displace the seatback 3.

The sector gear 24 is provided with the first protrusion 24B and thesecond protrusion 24C that are positioned with a space therebetween inthe rotational direction of the sector gear 24. In the state where thefirst protrusion 24B and the press pin 25 contact each other, the secondprotrusion 24C is placed in the non-contact state with the press pin 25.And, the press pin 25 is always present between the first protrusion 24Band the second protrusion 24C without being affected by the position ofthe seatback 3.

According to the aforementioned configuration, in the seatback rotatingdevice 20, one of the protrusions the first protrusion 24B or the secondprotrusion 24C contacts the press pin 25 and, in response to this, theseatback 3 starts rotating due to the rotational force.

The second protrusion 24C is situated at the position that is displacedwith respect to the first protrusion 24B in the rotational direction ofthe sector gear 24. And, the press pin 25 is always present between thefirst protrusion 24B and the second protrusion 24C without beingaffected by the position of the seatback 3.

Thus, the aforementioned configuration enables the seatback 3 to befreely and rotationally displaceable in a section defined between thefirst protrusion 24B and the second protrusion 24C. Accordingly, theuser of the vehicle seat 1 is allowed to rotationally displace theseatback 3 by manual operation. In other words, with the vehicle seat 1of the present embodiment, it is possible to rotationally displace theseatback 3 by manual operation and, at the same time, it is possible toinhibit the rotation speed of the seatback 3 from excessivelyincreasing.

The controller 26 rotates the electric motor 21 in the forwarddirection, to thereby bring the first protrusion 24B and the press pin25 into contact with each other to apply the rotational force to theseatback 3. Thereafter, the controller 26 can execute the tilt controlmode in which, in response to the seatback 3 reaching the firstposition, the electric motor 21 is rotated in the reverse direction tobring the first protrusion 24B back to the second position. According tothis, the user can rotationally displace the seatback 3 by manualoperation between the first position and the second position.

The second position is a position for placing the seatback 3 in theseatable state (the first standing position). Therefore, the user canplace the seatback 3, which is tilted, in the seatable state by manualoperation.

The second protrusion 24C is positioned in the range defined withrespect to the press pin 25 when the seatback 3 is placed in the tiltedstate and the first protrusion 24B is placed in the second position.This allows the seatback 3 to immediately and rotationally start beingdisplaced into the seatable state in conjunction with start of therotation of the electric motor 21.

When the sector gear 24 is placed in the standby state, the gap lengthL1 along the rotational direction of the sector gear 24 from the firstprotrusion 24B to the press pin 25 is smaller than the gap length L2along the rotational direction of the sector gear 24 from the secondprotrusion 24C to the press pin 25.

With the above configuration, in the seatback rotating device 20, one ofthe protrusions the first protrusion 24B or the second protrusion 24Ccontact the press pin 25 and, in response to this, the seatback 3 startsrotating due to the rotational force.

In the standby state, the gap length L1 along the rotational directionof the sector gear 24 allows the seatback 3 to be displaceable to thesecond standing position with the sector gear 24 being positioned in thestandby state. Accordingly, the occupant can displace the seatback 3 tothe second standing position when the sector gear 24 is placed in thestandby state.

Second Embodiment

The sector gear 24 of the above-described embodiment is configured notto be able to rotate frontward beyond the first position. In contrast,the sector gear 24 of the present embodiment is rotatable until theseatback 3 is placed in the tilt position.

Hereinafter, descriptions are given to differences between the firstembodiment and the second embodiment. The same constituent feature(s) asin the first embodiment is labelled with the same reference numeral inthe first embodiment and therefore, overlapping descriptions are omittedin the second embodiment.

Specifically, as with the second sensor 26B, the first sensor 26A of thesecond embodiment is configured with a limit switch or a proximityswitch. As shown in FIG. 21, the controller 26 receives an output signalof a third sensor.

The third sensor 26C outputs a signal (hereinafter, referred to as atilt signal) to the controller 26 in response to the seatback 3 reachingthe tilt position, the tilt signal indicating that the seatback 3reaches the tilt position. As with the first sensor 26A of the firstembodiment, the third sensor 26C detects the tilt position takingadvantage of increase in value of a conduction current flowing to theelectric motor 21.

During execution of the tilt control mode, the controller 26 rotates theelectric motor 21 in the forward direction until receiving the tiltsignal. In other words, the seatback 3 starts rotating to the tiltposition due to its own weight upon reaching the first position.

In a case where the controller 26 does not receive the tilt signalwithin a specified time after the seatback 3 reaches the first position,the controller 26 rotates the electric motor 21 in the forward directionuntil receiving the tilt signal. In response to receipt of the tiltsignal, the controller 26 rotates the electric motor 21 in the reversedirection, to thereby bring the sector gear 24 back to the standby state(see, FIG. 15).

Other Embodiments

The second position of the above described embodiments is a position ofthe first protrusion 24B in which the sector gear 24 is placed in thestandby state. However, the present disclosure is not limited hereto.The second position may be, for example, a position of the firstprotrusion 24B in which the sector gear 24 is placed in a state otherthan the standby state.

The position “specified first position” of the above-describedembodiments is set between the tilt position and the first standingposition. However, the present disclosure is not limited hereto. Theposition “specified first position” may be, for example, a positionother than the position between the tilt position and the first standingposition.

The second protrusion 24C of the above-described embodiments isconfigured to be positioned in the specified area defined with respectto the press pin 25 when the seatback 3 is placed in the tilt positionand the first protrusion 24B is placed in the second position. However,the present disclosure is not limited hereto.

According to the above-described embodiments, the controller 26 rotatesthe electric motor 21 in the forward direction, to thereby bring thefirst protrusion 24B and the press pin 25 into contact with each otherto apply the rotational force of the electric motor 21 to the seatback3. Then, in response to the seatback 3 reaching the first position, thecontroller 26 rotates the electric motor 21 in the reverse direction tobring the first protrusion 24B back to the second position. However, thepresent disclosure is not limited hereto.

The above-described embodiments have a configuration in which, when theseatback 3 is placed in the first standing position, the sector gear 24is in a position that creates a gap between the first protrusion 24B andthe press pin 25 and a gap between the second protrusion 24C and thepress pin 25. However, the present disclosure of this specification isnot limited hereto.

The above-described embodiments have a configuration in which, in thestandby state, the gap length L1 along the rotational direction of thesector gear 24 is small relative to the gap length L2 along therotational direction of the sector gear 24. However, the presentdisclosure is not limited hereto.

Specifically, the present disclosure may be configured, for example,such that the gap length L1 along the rotational direction of the sectorgear 24 and the gap length L2 along the rotational direction of thesector gear 24 are the same in the standby state, or may be configuredsuch that the gap length L1 along the rotational direction of the sectorgear 24 is greater than the gap length L2 along the rotational directionof the sector gear 24 in the standby state.

According to the above-described embodiments, in the standby state, thegap length L1 along the rotational direction of the sector gear 24allows the seatback 3 to be displaced to the second standing positionwith the sector gear 24 being positioned in the standby state. However,the present disclosure is not limited hereto.

The above-described embodiments described examples of a vehicle seat fora vehicle. Nevertheless, the present disclosure should not be limited tothese examples and may be applied to seats used in other vehicles, suchas railroad vehicles, ships and boats, and aircrafts, as well asbuilt-in seats used in theaters, households, and the like.

Furthermore, the present disclosure should not be limited to theabove-described embodiments as long as it falls within the spirit of theinvention disclosed in the disclosure described in the above-describedembodiments. Accordingly, the present disclosure may be configured incombination of at least two of the above-described embodiments or may bethe above-described embodiments configured without either theconfiguration requirements described in the drawings or the elementsdescribed with reference numerals.

What is claimed is:
 1. A seatback rotating device comprising: anelectric motor generating a rotational force that is used torotationally displace a seatback of a vehicle seat; and an applicationmechanism enabling application of the rotational force to the seatback,the application mechanism having a configuration that enables theseatback to be self-rotatable with gravity applied to the seatback inresponse to the rotational force being applied to the seatback.
 2. Theseatback rotating device according to claim 1, wherein the applicationmechanism includes: a rotor rotating in response to the rotationalforce, the rotor including a first protrusion and a second protrusionthat protrude in a radial direction of the rotor; and an abutment targetportion integrally and rotationally displaced with the seatback, theabutment target portion enabling one of the first protrusion or thesecond protrusion to contact the abutment target portion and theabutment target portion experiencing the rotational force in response tocontact with one of the first protrusion or the second protrusion,wherein the second protrusion is disposed in a position that isdisplaced with respect to the first protrusion in a rotational directionof the rotor, the position of the second protrusion placing the secondprotrusion in a non-contact state with the abutment target portion in astate where the first protrusion and the abutment target portion contacteach other, and wherein the abutment target portion is always presentbetween the first protrusion and the second protrusion without beingaffected by a position of the seatback.
 3. The seatback rotating deviceaccording to claim 2, wherein the seatback rotating device furthercomprises a controller that controls operation of the electric motor,and wherein the controller enables execution of a control mode in whichthe electric motor is rotated in a forward direction, to thereby bringthe first protrusion and the abutment target portion into contact witheach other to apply the rotational force to the seatback, the seatbackthereafter reaches a specified first position, and, in response to theseatback reaching the specified first position, the electric motor isrotated in a reverse direction to bring the first protrusion back to aspecified second position.
 4. The seatback rotating device according toclaim 3, wherein the second protrusion is situated in a specified areadefined with respect to the abutment target portion when the seatback isplaced in a tilted state and the first protrusion is placed in thesecond position.
 5. The seatback rotating device according to claim 3,wherein the seatback rotating device further comprises a sensor thatoutputs a signal to the controller in response to the seatback reachinga tilt position, the signal indicating that the seatback reaches thetilt position, and wherein, during execution of the control mode, thecontroller rotates the electric motor in the forward direction untilreceiving the signal.
 6. The seatback rotating device according to claim4, wherein the seatback rotating device further comprises a sensor thatoutputs a signal to the controller in response to the seatback reachinga tilt position, the signal indicating that the seatback reaches thetilt position, and wherein, during execution of the control mode, thecontroller rotates the electric motor in the forward direction untilreceiving the signal.